Composition and Structure of Bovine Milk Lipids Introduction p. 1 Fatty Acids p. 3 Origins of the Fatty Acids p. 4 Saturated Fatty Acids p.

Transcription

1 Composition and Structure of Bovine Milk Lipids Introduction p. 1 Fatty Acids p. 3 Origins of the Fatty Acids p. 4 Saturated Fatty Acids p. 5 Cis-unsaturated Fatty Acids p. 5 Trans-unsaturated Fatty Acids p. 7 Minor Fatty Acids p. 9 Variations in Fatty Acid Composition p. 10 Triacylglycerols p. 11 Structure of Triacylglycerols p. 13 Composition of Triacylglycerols p. 14 Polar Lipids p. 19 Composition and Structure p. 21 Ceramides and Gangliosides p. 25 Health Issues p. 27 Minor Constituents p. 27 Sterols p. 27 Carotenoids p. 28 Fat-soluble Vitamins p. 28 Flavour Compounds p. 29 Milk Fat From Different Animal Species p. 30 Gross Composition p. 30 Fatty Acids p. 31 Triacylglycerols p. 33 Polar Lipids p. 34 Bibliography p. 35 Milk Fat: Origin of Fatty Acids and Influence of Nutritional Factors Thereon Abstract p. 43 Introduction p. 44 Origin of the Fatty Acids in Milk Fat p. 45 Overview p. 45 Fatty Acid Transport p. 45 Lipoprotein Lipase p. 47 Transport of Long-Chain Fatty Acids into Mammary Cells p. 48 Summary of the Supply of Long-Chain Fatty Acids to the Mammary Gland p. 50 Uptake of Non-Lipid Metabolites by Lactating Mammary Glands p. 51 Fatty Acid Synthesis in Mammary Glands p. 52 Sources of Carbon and Reducing Equivalents for Fatty Acid Synthesis p. 52 Acetyl-CoA Carboxylase p. 55 Fatty Acid Synthase p. 58

2 Regulation of Acyl Chain Length p. 60 Stearoyl-CoA Desaturase p. 62 Triacylglycerol Synthesis p. 63 Fatty Acid Esterification by the Monoacylglycerol Pathway p. 66 Synthesis of Complex Lipids p. 66 Synthesis of Phospholipids p. 67 Sphingolipids p. 68 Cholesterol p. 68 Physiological Factors That Influence Milk Fat Composition p. 69 Genetics p. 69 Stage of Lactation p. 69 Effects of Dietary Fat on the Composition of Milk Fat p. 71 Effects of Low-fat Diets p. 71 Effects of Specific Fatty Acids p. 71 Feeding for Specific Milk Fatty Acid Profiles p. 73 Supplementation with Oilseeds and Commercial Fats p. 74 Low Milk Fat Syndrome p. 78 Milk Fat Composition and Quality p. 78 Acknowledgment p. 80 Bibliography p. 80 Conjugated Linoleic Acid: Biosynthesis and Nutritional Significance Abstract p. 93 Introduction p. 94 Dietary Sources p. 96 Analytical Challenges p. 97 Origin of CLA in Milk Fat p. 99 Lipid Metabolism in the Rumen p. 99 cis-9, trans-11 CLA (Rumenic Acid) p. 102 trans-7, cis-9 CLA p. 104 The [Delta superscript 9]-Desaturase Enzyme System p. 105 Other CLA Isomers p. 106 Modification of CLA Content in Milk Fat p. 107 Dietary and Nutritional Effects p. 108 Physiological Factors p. 111 Manufacturing and Product Quality Considerations p. 112 Biological Effects of CLA Isomers p. 114 trans-10, cis-12 CLA and Lipid Metabolism p. 114 Rumenic Acid and Human Health p. 120 Bibliography p. 125 Intracellular Origin of Milk Fat Globules and the Nature of the Milk Fat Globule Membrane Introduction p. 137

3 Intracellular Origin and Growth of Milk Fat Globules p. 138 Intracellular Transit of Lipid Droplets p. 142 Secretion of Milk Fat Globules p. 143 Isolation and Gross Composition of MFGM p. 150 Lipid Composition of the MFGM p. 151 Enzymes Associated with the MFGM p. 153 Proteins of the MFGM p. 155 Molecular Organization of the MFGM p. 163 Perspectives p. 164 Acknowledgements p. 164 Bibliography p. 165 Physical Chemistry of Milk Fat Globules Introduction p. 173 The Nature and Size Distribution of Milk Fat Globules p. 173 Differences in the Composition of Milk Fat Globules p. 177 Fat Crystals in Globules p. 177 Colloidal Interactions p. 179 Physical Instability of Emulsions p. 181 Separation of Milk p. 183 Cold Agglutination p. 184 Coalescence and Partial Coalescence p. 188 Rebodying p. 190 Factors that Affect the Surface Layers of Fat Globules in Milk and Cream p. 191 Disruption of Globules p. 192 Milk Fat Globules in Homogenized Milk and Cream p. 196 Milk Fat Globules in Recombined Milk p. 198 Free Fat p. 200 Influence of Fat Globules on Rheological Properties of Milk and Cream p. 201 Volume Fraction of the Dispersed Phase p. 202 Rheology of the Component Phases p. 202 Droplet Size p. 203 Colloidal Interactions p. 203 Particle Charge p. 203 Conclusions p. 204 Bibliography p. 204 Composition, Applications, Fractionation, Technological and Nutritional Significance of Milk Fat Globule Membrane Material Introduction p. 213 Nutritional and Physiological Significance of the Milk Fat Globule Membrane p. 214 Biological Significance of Native Globules p. 216 MFGM Consumption Studies: Physiological and Nutritional Effects p. 218 Composition and Bioactivity of Individual Components p. 219

4 Phospholipids p. 219 Ceramide Sphingolipids and Glycosphingolipids p. 220 Proteins p. 223 Butyrophilin p. 224 Mucins p. 226 Xanthine Oxidoreductase p. 228 Fractionation and Technological Significance of Milk Fat Globule Membrane Material p. 229 Effect of Processing on the Composition and Functionality of the MFGM p. 230 Isolation of MFGM p. 232 Application and Utilization of MFGM as a Functional Ingredient in Foods p. 235 Conclusions and Future Research Directions p. 237 Bibliography p. 238 Crystallization and Rheological Properties of Milk Fat Introduction p. 245 Crystallization of Milk Fat p. 245 Introduction p. 245 Nucleation of Milk Fat p. 247 Growth of Milk Fat Crystals p. 248 Crystallization, Melting and Mixed Crystal Formation p. 248 Polytypism and Polymorphism p. 250 Structure and Rheology of Fat Crystal Networks p. 254 Milk Fat and Butter Crystal Networks p. 254 Methods used to Determine the Rheological Properties of Milk Fat p. 254 Rheology of Milk Fat p. 262 Modeling Fat Crystal Networks and Relating Structure to Rheology p. 267 Modifying the Crystallization and Rheology of Milk Fat p. 271 Manipulations of Butter Composition p. 271 Manipulations During Processing p. 274 Some Case Studies. Milk Fat Crystallization: Structure and Rheological Properties p. 277 Effect of Cooling Rate on Milk Fat Crystallization and Rheology p. 277 Effect of Supplementation with Algae Meal on Milk Fat Crystallization and Rheology p. 279 Effect of Minor Components on Milk Fat Crystallization and Rheology p. 280 Conclusion p. 281 Bibliography p. 281 Milk Fat: Physical, Chemical and Enzymatic Modification Introduction p. 293 Physical Modification of Milk Fat p. 294 Fractionation p. 295 Physical Blends of Milk Fat with Other Fats and Oils p. 309

5 Modification of Milk Fat Properties by Addition of Minor Lipids p. 311 Chemical Modification of Milk Fat p. 313 Hydrogenation p. 313 Chemical Interesterification p. 314 Enzymic Modification of Milk Fat p. 316 Enzymic Interesterification p. 317 Enzymic Hydrolysis p. 321 Cholesterol Reduction p. 322 Distillation Processes p. 322 Supercritical CO[subscript 2] Extraction p. 323 Treatment with Adsorbents p. 323 Treatment with Enzymes p. 324 Future Trends p. 324 Acknowledgements p. 325 Bibliography p. 325 Chemistry and Technology of Butter and Milk Fat Spreads Introduction p. 333 Legislation p. 333 Emulsion Stability p. 334 Consumer Pressures for Change p. 334 Technical Aspects of Butter Manufacture p. 336 Chemical and Physical Principles p. 336 Technical Challenges in the Processing of Fat Spreads p. 339 Rates of Microbial Growth p. 339 Phase Inversion p. 340 Technology of Spread Manufacture p. 340 Processing p. 340 Fundamental Aspects of Emulsions p. 342 Emulsions: Theory, Rheology and Stability to Inversion p. 342 Effects of Ingredients on Emulsion Stability p. 348 Fat p. 348 Emulsifiers p. 350 Proteins p. 351 Hydrocolloid Stabilizers p. 353 Sodium Chloride p. 354 Disodium Phosphate and Trisodium Citrate p. 354 ph p. 354 Interactions of Ingredients p. 354 Interactions of Ingredients in Low-Fat Spreads p. 355 Bibliography p. 357 Further Reading p. 362

6 Significance of Milk Fat in Cream Products Introduction p. 365 Coffee Cream p. 366 Whipping Cream p. 368 Cream Liqueurs p. 372 Cultured Cream p. 373 Bibliography p. 374 Significance of Milk Fat in Cheese Introduction p. 377 Effect of Fat on Cheese Composition p. 379 Fat Content p. 379 Effect of Degree of Fat Emulsification as Influenced by Homogenization of Milk, Cream and/or Curd p. 382 Contribution of Fat to the Microstructure of Cheese p. 385 Microstructure of Rennet-Curd Cheese p. 385 Microstructure of Pasteurized Processed Cheese Products (PCPs) and Analogue Cheese p. 391 Products (ACPs) Effect of Fat Level on Microstructure p. 392 Effect of Fat Emulsification on Microstructure p. 393 Effect of Fat on Heat-induced Changes in Microstructure p. 395 Effect of Fat on Cheese Yield p. 397 Effect of Fat on Cheese Microbiology p. 401 Effect of Fat on Proteolysis p. 403 Primary Proteolysis p. 403 Secondary Proteolysis p. 406 Contribution of Lipolysis and Catabolism of Free Fatty Acids (FFA) to Cheese Flavor p. 407 Lipolysis p. 408 Metabolism of Fatty Acids p. 410 Effect of Fat on the Fracture-Related Properties of Unheated Cheese p. 413 Effect of Fat Content on Fracture Properties p. 414 Effect of Solid-to-Liquid Fat Ratio on Fracture Properties p. 414 Effect of Homogenization of Milk or Cream, and Degree of Fat Emulsification on Fracture Properties p. 418 Effect of Fat on the Functional Properties of Heated Cheese p. 419 Effect of Fat Level on Cooking Properties p. 419 Effect of Milk Homogenization and Degree of Fat Emulsification p. 425 Effect of Milk Fat Fraction on Cooking Properties p. 427 Bibliography p. 428 Ice Cream Overview of Ice Cream Ingredients and Manufacture p. 441 Sources of Fat in Ice Cream p. 443 Contribution of Fat to the Structure of Ice Cream p. 444

7 Contribution of Fat to Ice Cream Texture and Flavor p. 447 Bibliography p. 448 Significance of Milk Fat in Milk Powder Introduction p. 451 Overview of Milk Powder Manufacture p. 452 Significance of Milk Fat during Powder Manufacture p. 455 Significance of Milk Fat for the Flavor of Milk Powder p. 457 Effect of Pre-heat Treatment on Oxidative Stability p. 457 Influence of Moisture Content and Water Activity on the Oxidation of Fat in Milk Powder p. 458 Effect of Oxygen Content and Packaging the Oxidation of Fat in Milk Powder p. 458 Lipid Oxidation Products p. 460 Role of Fat in the Physical Properties of Milk Powder p. 461 Bibliography p. 462 Significance of Milk Fat in Infant Formulae The Nutritional Role of Lipids p. 467 Fatty Acid Profile and Fat-Soluble Vitamins of Human Milk and Infant Requirements p. 469 Biological Benefits of Milk Fatty Acids p. 473 Formulation of Infant Formula Using Milk Fat as an Ingredient p. 473 Summary p. 476 Bibliography p. 477 Lipolytic Enzymes and Hydrolytic Rancidity Summary p. 481 Introduction p. 481 The Enzymes p. 483 Cows' Milk Lipase p. 483 Human Milk Lipases p. 486 Milk Lipases of Other Species p. 487 Esterases of Cows' Milk p. 489 Lipases of Psychrotrophic Bacteria p. 490 Phospholipases p. 494 Lipolytic Enzymes in Milk Product Manufacture p. 495 Causes of Hydrolytic Rancidity in Milk and Milk Products p. 496 Induced Lipolysis p. 497 Spontaneous Lipolysis p. 501 Mastitis p. 508 Microbial Lipolysis p. 509 Detrimental Effects of Lipolysis in Milk and Milk Products p. 511 Flavor Defects p. 511 Technological Consequences p. 516 Beneficial Effects of Lipolysis in Milk and Milk Products p. 517

8 Production of Desirable Flavor p. 517 Digestion of Milk Fat p. 518 Analytical Methods p. 519 Free Fatty Acids p. 519 Lipase Activity p. 524 Prevention of Hydrolytic Rancidity p. 529 Bibliography p. 530 Lipid Oxidation Introduction p. 557 Mechanism of Lipid Autoxidation p. 558 Oxidation Products and Off-Flavors p. 559 Spontaneous Oxidation in Milk p. 561 Factors that Affect the Oxidation of Lipids in Milk and Milk Products p. 563 Oxygen p. 564 Light p. 568 Metals p. 570 Antioxidants p. 572 Ascorbic Acid p. 573 Tocopherols p. 574 Carotenoids p. 575 Thiols p. 576 Proteins and Enzymes p. 577 Products of Browning Reactions p. 579 Milk Fat Globule Membrane (MFGM) p. 580 Storage Temperature p. 582 Water Activity p. 582 Measurement of Lipid Oxidation p. 583 Bibliography p. 585 Nutritional Significance of Milk Lipids Introduction p. 601 Dietary Fat and Obesity p. 602 Randomised Control Trials p. 603 Safety of Low-Fat, High-Carbohydrate Diets p. 603 Energy Value of Milk Fat p. 603 Dietary Fat and Cancer p. 604 Colon Cancer p. 605 Breast Cancer p. 606 Prostate Cancer p. 607 Comment p. 608 Milk Fat and Coronary Heart Disease p. 608 Plasma Cholesterol and CHD p. 609

9 Saturated Fatty Acids and CHD p. 610 Dietary Cholesterol and CHD p. 612 Intervention Studies for CHD Prevention p. 613 Comment p. 614 Trans Fatty Acids and CHD p. 615 Clinical Studies p. 615 Epidemiological Studies p. 616 Biological Explanation for the Disparate Effects p. 616 RA and Atherosclerosis p. 617 Anti-Cancer Agents in Milk Fat p. 618 Rumenic Acid p. 619 Sphingolipids and Colon Cancer p. 622 Butyric Acid p Methyltetradecanoic Acid p. 628 Ether Lipids p. 628 Cholesterol p. 628 [beta]-carotene and Vitamin A p. 629 Vitamin D and its Metabolites p. 630 Anti-Cancer Agents from Feed p. 630 Milk Fat and Cancer p. 631 Other Nutritional Benefits p. 631 Conclusions p. 632 Bibliography p. 633 Oxysterols: Formation and Biological Function Introduction p. 641 Formation of Oxysterols p. 642 Cholesterol Autoxidation p. 643 Initiation of Cholesterol Oxidation p. 652 Oxysterols in Food Products p. 653 Oxysterols in Dehydrated Systems p. 655 Oxysterols in High-Fat Products p. 656 Other Factors Involved in Oxysterol Formation p. 657 Sources of Oxysterols In Vivo p. 657 Absorption of Dietary Oxysterols p. 658 Oxysterols Formed Endogenously by Nonenzymatic Oxidation p. 659 Oxysterols Formed Enzymatically p. 661 Biological Effects of Oxysterols p. 662 Effects of Oxysterols on Cell Membranes p. 662 Oxysterols and Apoptosis p. 663 Oxysterols and Atherosclerosis p. 665 Conclusions p. 667

10 Bibliography p. 667 High Performance Liquid Chromatography and Gas Chromatography Methods for Lipid Analysis Introduction p. 675 Quantification of FFAs p. 676 Gas Chromatography p. 676 High Performance Liquid Chromatography p. 678 Isolation of FFA p. 679 GC Analysis p. 683 HPLC Analysis p. 685 Conjugated Linoleic Acid p. 686 Lipid-Derived Volatile Aroma and Flavor Compounds p. 687 Gas Chromatography Mass Spectrometry p. 687 Isolation and Concentration of Volatile Lipid-Derived Components p. 688 Tri-, Di- and Mono-Acylglycerols p. 690 Chromatographic Methods for the Analysis of Lipolytic Activity p. 692 Bibliography p. 692 Spectroscopic Techniques (NMR, Infrared and Fluorescence) for the Determination of Lipid Composition and Structure in Dairy Products Spectroscopic Techniques Used to Study Fats in Dairy Products p. 697 Infrared Spectroscopy p. 697 Fluorescence Spectroscopy p. 698 Nuclear Magnetic Resonance p. 700 Characterization of Dairy Products, Including Cheeses p. 701 Direct Determination of the Concentrations of Different Compounds p. 701 Direct Determination of the Structure of Fats in Dairy Products p. 702 Conclusion p. 705 Bibliography p. 706 Applications of Ultrasound to Analysis/Quantitation of Dairy Lipids Introduction p. 709 Theory of Ultrasound Propagation through Solid and Liquid Lipids p. 711 Introduction p. 711 Physical Determinants of Attenuation, Phase and Group Velocity p. 712 Ultrasound Methods for Characterizing Dairy Lipids p. 716 Tracking Crystallization p. 716 Conclusions p. 720 Acknowledgements p. 721 Bibliography p. 721 Physical Characterization of Milk Fat and Milk Fat-Based Products Introduction p. 725 Thermal Properties: Phase Change Behavior p. 726 Melting and Solidification Points: Introduction p. 726

11 Melting Points p. 726 Solidification Point p. 729 Dilatometry p. 729 Nuclear Magnetic Resonance p. 731 Differential Scanning Calorimetry p. 731 X-Ray Diffraction (XRD) p. 740 Combined DSC and XRD p. 745 Coupled DSC and XRD p. 746 Thermal Properties: Critical Temperatures p. 750 Rheological Properties p. 751 Introduction p. 751 Rheological Behavior and Material Classification p. 751 Rheological Characterization of Materials p. 752 Viscometers and the Measurement of Fundamental Viscous Properties p. 753 Solids Rheometers and the Measurement of Fundamental Elastic Properties p. 756 Measurement of Linear Viscoelastic Properties p. 759 Measurement of Nonlinear Viscoelastic Properties p. 760 Measurement of Extensional Viscosity p. 761 Application of Rheological Techniques to Milk Fat and Milk Fat-Based Dairy Products p. 762 Density p. 765 Electromagnetic Properties p. 766 Refractive Index p. 766 Color p. 767 Dielectric Properties p. 768 Electrical Conductivity p. 770 Functional Properties p. 770 Milk Fat and Butter p. 771 Ice Cream p. 771 Chocolate p. 771 Whole Milk Powders p. 771 Acknowledgements p. 772 Bibliography p. 772 Index p. 779 Table of Contents provided by Blackwell's Book Services and R.R. Bowker. Used with permission.